The influence of moderate or deep neuromuscular block status on anesthetic depth monitoring system during total intravenous anesthesia using propofol and remifentanil: A randomized trial

The neuromuscular block state may affect the electroencephalogram-derived index representing the anesthetic depth. We applied an Anesthetic Depth Monitoring for Sedation (ADMS) to patients undergoing laparoscopic cholecystectomy under total intravenous anesthesia, and evaluated the requirement of propofol according to the different neuromuscular block state. Adult patients scheduled to undergo laparoscopic cholecystectomy were enrolled and randomly assigned to either the moderate (MB) or deep neuromuscular block (DB) group. The UniCon sensor of ADMS was applied to monitor anesthetic depth and the unicon value was maintained between 40 and 50 during the operation. According to the group assignment, intraoperative rocuronium was administered to maintain proper neuromuscular block state, moderate or deep block state. The unicon value, electromyography (EMG) index, and total dose of propofol and rocuronium were analyzed. At similar anesthetic depth, less propofol was used in the DB group compared to the MB group (6.19 +/- 1.36 in the MB mg/kg/h group vs 4.93 +/- 3.02 mg/kg/h in the DM group, p = 0.042). As expected, more rocuronium were used in the DB group than in the MB group (0.8 +/- 0.2 mg/kg in the MB group vs 1.2 +/- 0.2 mg/kg in the DB group, p = 0.023) and the EMG indices were lower in the DB group than in the MB group, at several time points as follows: at starting operation (p < 0.001); at 15 (p = 0.019), 45 (p = 0.011), and 60 min (p < 0.001) after the initiation of the operation; at the end of operation (p = 0.003); and at 5 min after the administration of sugammadex (p < 0.001). At similar anesthetic depth, patients under the deep neuromuscular block state required less propofol with lower intraoperative EMG indices compared to those under the moderate neuromuscular block state during general anesthesia.